In this study, boron nitride aerogel (BN_aerogel) and phosphorus-doped boron nitride aerogel (P-BN_aerogel) were prepared using the sol-gel method and the low-dimensional boron nitride (BN) assembly method for the treatment of heavy metal ions in wastewater. The results showed that P-BN_aerogel had a large specific surface area (465.4 m^2/g). The introduction of phosphorus (P) resulted in the addition of P—O—C and P—O funetional groups, which facilitated stronger binding of heavy metal ions to the adsorbent. The optimal adsorption temperature for both aerogels was 25 ℃. P-BN_aerogel, and its adsorption capacity for Cu^2+ was enhanced by 14.4% compared to BN_aerogel. The maximal adsorption amounts of Zn^2+, Cu^2+, Cd^2+ and Pb^2+ by P-BN_aerogel 338.5, 413.3, 253.9, and 234.8 mg/g, respectively. The adsorption prcess of BN_aerogel involved a surface monolayer adsorption dominated by chemical adsorption and physical adsorption. Both BN_aerogel and P-BN_aerogel demonstrated high removal efficiency for Cu^2+ in mixed heavy metal solutions, with P-BN_aerogel exhibiting selective adsorption for Cu^2+. Benefitting from the stable coordination environment and inereased adsorption sites provided by P doping, the removal rate of P-BN_aerogel for each heavy metal was higher than that of BN_aerogel. Additionally, the ultra-light density and controllable structure of P-BN_aerogel, made it suitable for a wider range of applications, offering economic advantages.